**Article citation information:**

Więckowski, A. Differentiated road construction
costs. *Scientific Journal of Silesian
University of Technology. Series Transport*. 2017, **96**, 205-213. ISSN: 0209-3324. DOI: https://doi.org/10.20858/sjsutst.2017.96.19.

Andrzej
WIĘCKOWSKI**[1]**

**DIFFERENTIATED ROAD
CONSTRUCTION COSTS **

**Summary**. In
the context of the variability of road construction costs in Europe, the prices
of 24 contracts for sections of motorways in Poland, concluded in 2016 by the
General Directorate for National Roads and Motorways, were analysed. According
to the proposed method of calculation, taking into account the fact that road
prices in tunnels were several times higher than in other sections, the unit
cost of the road in a tunnel (between Naprawa and Skomielna Biała) was
assessed, compared to the road in a tunnel in Slovenia. Based on the study of
the values of standard deviations and coefficients of variation, it can be
stated that there is a small price differentiation in S-class roads on flat and
corrugated areas, and very large price differentials on the roads that bypass
cities and in mountainous terrain.

**Keywords:**
road costs; motorways; express roads; tunnels

**1. INTRODUCTION**

High construction costs, which total
as much as several million euros per km of state-of-the-art road, pose a major
obstacle to the rapid development of the road network [2, 7, 11]. Such costs
highly depend on road location. Capital expenditure
(capex) within cities is much higher than outside them. The lower the
number of urban obstacles and the easier the access to areas outside the city
offer the simpler, less burdensome and quicker execution of works, which
translates into lower construction costs. In turn, in mountain areas, where
there is a need for strengthening embankment and excavation slopes with
retaining walls and anchors, as well as a need for building many bridges and
even tunnels, costs are much higher than when constructing roads in undulated
and flat areas.

Local conditions often require the
transfer of entire habitats of flora and fauna, together with building special
passes, changing watercourses, creating
roadside greens or constructing acoustic screens. The costs are also affected
by fluctuating prices in the construction industry.

The article presents the costs of
motorway construction across Europe, as well as an analysis of capex per road
sections with various tunnel lengths. The analysis also considers varying
contract prices involving the construction of 24 S-class road sections,
concluded in 2016 in Poland.

**2. AREAS GENERATING MOTORWAY CONSTRUCTION COSTS**

Apart from consuming several dozen
metres of the width of a belt of land directly intended for the road, motorways
contribute to pollution levels with exhaust gases and significant noise
spreading for several kilometres. Furthermore, the area is artificially divided
into separate parts. There is a need for transferring habitats and constructing
passes for animals, as well as other pro-environmental solutions. As a result,
according to [2], the value of environmental elements totals about 18%, while
sometimes even reaching 35%, of motorway capex (Fig. 1). Costs relating to land
purchase and the relocation of residents total about 15%, while, in urban
areas, they can even reach up to 30% of the total investment value (such as
during the construction of the M74 motorway in Glasgow in 2009). Currently,
engineering costs amount to between 3% and 5%, expertise and consulting
typically total around 7%, while sometimes reaching up to 15% of the investment
value. Construction itself usually costs about 25% of the motorway value,
whereas administrative expenses of such projects total about 30%.

Fig. 1. Motorway construction cost
component generation areas

(own study, pursuant to [2])

**3. ROAD CONSTRUCTION COST VARIABILITY ACROSS
EUROPE**

When analysing road construction
costs across Europe, according to [9], in 1998, the lowest capex/km of a
motorway (on average in the entire road section analysed) totalled between EUR
1.9 million in Spain, in flat and undulated area, to EUR 12.5 million in
Switzerland, in a difficult mountain area (Fig. 2). For example, in France, the
cheapest 1 km of motorway was built for EUR 5.2 million, while the price was
about 23% higher in Germany, totalling EUR 6.4 million. With average costs
across all lands of EUR 10.6 million/km, the value of the cheapest roads in
Germany was 2.1 times lower than the value of the most expensive sections. In
Italy, the value of the most expensive road sections was four times higher than
that of the cheapest ones, while, in Switzerland, the proportion totalled 6.4
times.

Fig. 2. Motorway construction cost
variability in selected European countries, 1998

(own study, pursuant to [9])

In 2012, the average cost of
construction of 1 km of motorway in Germany totalled EUR 8.2 million/km (Fig.
3). This was 23% lower than in 1998 and 13% lower than the average construction
costs of such roads across Europe, which totalled EUR 9.4/km. In Poland,
despite the fact that the costs of motorway construction, according to [10],
decreased by 36%, compared with the costs from 2008, the average cost totalled
EUR 9.6 million/km in 2012, which was still 2% higher than the average value in
Europe. However, after a reduction of 39% in the costs of S-type express roads in
Poland, compared to 2008, their average value totalled EUR 8.7 million/km,
which was just by 7.5% lower than the average cost of motorway construction in
Europe.

Fig. 3. Average costs of motorway
construction in 2012

(own elaboration based on [10])

**4. COMPARISON OF ROAD CONSTRUCTION COSTS
WITH VARIOUS TUNNEL LENGTHS **

In order to confront the issue of
road construction costs with various proportions of tunnel length p, as
compared to total road section length, the calculation can be performed according
to the following equation:

*k _{p }= k_{t }p* +

where* k _{p }*is the
average cost of construction of 1 km of road for the adopted

In Slovenia, where the average cost
of motorway construction was, as stated above, 22% lower than the European
average, the construction of a road, whose length ld = 4.5 km, with a tunnel
whose length lt = 1.5 km, totalled as much as EUR 59 million/km, meaning it was
6.3 times higher than the European average, and also eight times higher than
the average cost of motorways in that country (cf. Fig. 3).

A section of the S7
road from Naprawa to Skomielna Biała (a dual carriageway with a two-chamber
tunnel [1, 7]), with a length of 3.05 km and a tunnel stretching 2.057 km, will
cost, according to the tender results, EUR 79.4 million/km on average (which is
34.6% more expensive than an average section of road with a tunnel in Slovenia
[2]). When considering, however, the same proportion of *p *= 0.333, as in the case of Slovenian road, and with average S7
costs of *k _{t}* = EUR 104.5
million/km for the tunnel, and

In the case of a 4.7
km section of S69 from Szare to Laliki (single lane, with a single-chamber
tunnel [5, 8]), the construction cost on average totalled EUR 20.9 million/km.
When calculating, according to the same proportion of tunnel length to the
remaining road section, for *p *= 1/3,
as in Slovenia, the average cost should total EUR 27.5 million/km.

Given that road construction in
tunnels is several times more expensive than other sections of road, a
comparison of the unit costs of construction of such roads should involve the
same proportion *p* of tunnel length,
as compared to the remaining section of the road being analysed.

Fig. 4. Average costs per 1 km of the roads
analysed and when observing the proportion

p = 1:3 of tunnel length as compared to the total road section length (own
study)

**5. CONTRACTUAL PRICES FOR ROAD
CONSTRUCTION IN POLAND**

When analysing 24 contracts [4]
concluded by the General Director for National Roads and Motorways in 2016
[11], for the construction of S-class express roads (with two separate
double-lane carriageways, with a bearing strength of 115 kN/axle, emergency
lanes, bridges and pedestrian passes, passenger service areas, underpasses and
animal passes), there is a high difference in the average unit prices, ranging
from PLN 9.4 million to PLN 322.9 million/km (Fig. 5).

For assessing price differentiation,
V variability factor values were analysed according to the following equation:

*V *=* s / *_{},* *_{}* *≠ 0, (2)

where:* *

*s *– *s*tandard
deviation in a sample

_{} – arithmetic mean in a sample

According to Wawrzynek [6], if the
value of V variability factor remains within the interval <0%, 20%>, the
differentiation within the population is low. On V values falling in the next
interval (20%, 40%>, one can point to an average differentiation within
the population, whereas a high differentiation is observed in the case of
values falling in the range (40%, 60%>, and a very high differentiation
is found at V > 60%.

Fig. 5. S7 road construction contract prices in
Poland, as concluded in 2016

Average price for all contracts
under analysis totalled _{}= PLN 43 million/km, with standard deviation *s*_{24} = 63.3. The value of variability
factor *V*_{24} = 147.2%, which
is much higher than 60%, indicating a very high differentiation in prices.

**5.1. Roads constructed in flat and undulated
areas**

When analysing 14 contracts for
S-class road construction in the area of Poland north of Wrocław and Lublin,
comprising flat and undulated areas, the average costs of such roads totalled _{}= PLN 22.9 million/km, with standard deviation *s*_{14} = 3.4. As the value of
variability factor *V*_{14} = 14.8%, which is lower than 20%, according
to Wawrzynek [6], one can assume that the price differentiation was low.

**5.2. Bypass construction**

A different price distribution was
observed for contracts involving the construction of seven city bypasses. Rings
around large cities were several times more expensive (e.g., for Olsztyn: PLN
62.1 million/km) than in the case of smaller cities and towns (e.g., Bolków:
PLN 9.4 million/km). The average price of bypasses totalled _{}= PLN 31.3 million/km, with standard deviation *s*_{7} = 22.5. The value of
variability factor *V*_{7} =
71.9% is higher than 60%, which means a very high differentiation in prices.

**5.3. S7 express road sections**

In the Małopolska region, between
Krakow and Zakopane, in a difficult mountain area, involving the necessary
strengthening of embankment and excavation slopes with retaining walls and
anchors, and the need for constructing many bridges, as well as a
double-chamber tunnel, construction is much more expensive than construction in
flat areas. For example, the 7.6 km section between Lubień and Naprawa,
comprising 10 engineering facilities and six small bridges, as well as two
passenger service areas, will be built at an average cost of PLN 68.6
million/km, while the 6.1 km section between Skomielna and Rabka Zdrój, with
two road nodes and 17 bridges with a total length of about 2.3 km, the longest
of which being 992 m, will be built at an average cost of PLN 100.8 million/km.
The most difficult section, that is the 3 km stretch between Naprawa and
Skomielna Biała, with a double-chamber tunnel of 2.06 km, will be constructed
at a cost of PLN 322.9 million/km. The average price of these S7 road sections
total _{}= PLN 164.1 million/km, with standard deviation *s*_{3} = 138.5 and variability
factor *V*_{3} = 84.4%, which
is much higher than 60%, indicating a very high price differentiation.

**6. CONCLUSION **

Road infrastructure significantly interferes with the natural environment
(by occupying a large area and dividing it into separate parts, prompting
the need to transfer habitats of flora and fauna, construct passes and screens,
and change watercourses, as well as causing pollution with exhaust gases and
noise). As a result, the value of environmental elements totals about 18%
(sometimes even 35%) of motorway capex. The costs of land purchase and
transfers total about 15% (up to 30% in cities), whereas construction itself
usually constitutes 25%, while administrative expenses total about 30% of the
motorway value.

In 2012, the average
construction cost of motorways in Europe totalled about EUR 9.4 million/km. Low
costs were observed in Spain (EUR 6.7 million/km), while high costs were noted
in Austria (EUR 12.9 million/km). In Germany, motorway construction was about
7% cheaper than in 1998, current costs are lower by 13% compared to the
European average. In Poland, motorway construction costs total about EUR 9.6
million/km, which is 2% higher than average costs in Europe.

The most expensive
sections are the ones with tunnels. For example, compared to average motorway
construction costs in Slovenia, which total EUR 7.3 million/km (i.e., 22% lower
than the European average), a 4.5 km road section with a tunnel that is 1.5 km long costs EUR 59 million/km, which is eight times more expensive.
Similarly, a 3.05 km section of the S7 road from Naprawa to Skomielna Biała,
with a tunnel stretching 2.057 km, will cost, according to the tender results,
an average of EUR 79.4 million/km (i.e., 35% more expensive than in Slovenia). At the same time, with the same proportion of
tunnel length to the length of road analysed, as in Slovenia, *p* = 0.33, after calculating the cost of
the road section from Naprawa to Skomielna Biała, which is 9.9% lower than in
Slovenia. Therefore, any comparison of unit costs of the construction of such
roads (where roads in tunnels are several times more expensive than at other
sections) should involve the same proportion *p *of tunnel length as the remaining section of the road analysed.

The average price in the 24
contracts for S-class road construction, concluded in 2016 by the General
Director for National Roads and Motorways, totalled _{}= PLN 43 million/km. Certain contracts were characterized by
a very high differentiation in prices, with standard deviation *s*_{24} = 63.3 and variability
factor *V*_{24} = 147.2%.
Similarly, a very high price differentiation was observed for three sections of
the S7 road in the mountain area (_{}= PLN 164.1 million/km, *s*_{3}
= 138.5, *V*_{3} = 84.4%), as
well as in the case of seven city rings (_{}= PLN 31.3 million/km, *s*_{7}
= 22.5, *V*_{7} = 71.9%). In
flat and undulated areas, however, the prices for the 14 S-class road sections
in the area of Poland north of Wrocław and Lublin were characterized by low
price differentiation (_{}= PLN 22.9 million/km, *s*_{14}
= 3.4, V_{14} = 14.8%).

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Received 11.05.2017; accepted in revised form 20.08.2017

Scientific Journal of Silesian
University of Technology. Series Transport is licensed under a Creative
Commons Attribution 4.0 International License

[1]AGH University of Science and Technology, Faculty
of Mining and Geoengineering, Mickiewicza 30 Street, 30-059 Cracow, Poland. E-mail:
awiecko@agh,edu.pl